An interesting story ran on NPR recently, describing a “lost” paper of Einstein’s, which was never published because Einstein recognized that he’d made a mistake and therefore never submitted it for publication. Apparently there was some excitement surrounding this abandoned work because physicists had assumed it was a draft of a different paper – one that was published in 1931.
According to the story, Einstein’s Lost Theory Discovered, and It’s Wrong, this erroneous and never-published paper examined a possible explanation for then-recent observations by Edwin Hubble (also Georges Lemaitre), that the universe was expanding.
Faced with evidence that the universe was growing, Einstein apparently wanted to figure out why it wasn't filling up with empty space. His proposed solution is in this newly discovered paper. As the universe expanded, he suggested, new matter showed up to fill the gaps. New stars and galaxies would just pop up, according to Einstein's model, so that even as the universe grew, it would look the same.
Just to be clear, this theory is totally wrong. But for a little while Einstein thought it was right. The numbers made sense, because he had made a mathematical mistake. In the middle of a complicated calculation, he wrote a minus sign where he should have written a plus.
Why would Einstein necessarily have thought the theory was right? Couldn’t he plausibly have been just noodling around with it to see if it could make sense mathematically? And indeed:
Einstein eventually found his mathematical error. He crossed it out and realized his idea wouldn't work. Cormac O'Raifeartaigh says it looks like Einstein set it aside. Maybe he forgot about it.
The moral of the story seems to be that even the smartest people in the world make errors, but in this case, does it really count as an error if Einstein wrote it on some scratch paper and then caught it himself before sending it anywhere? And did anyone believe that Einstein didn’t make errors?
In fact, anyone who follows cosmology has probably heard an old story about Einstein proposing something called the cosmological constant, only to later call the thing his “biggest blunder”.
It’s odd that the NPR piece doesn’t acknowledge this tale, but the story does mention the book Brilliant Blunders by Mario Livio, an astrophysicist and also a very good science writer. The book contains a wonderful chapter on Einstein and his alleged biggest blunder. By Livio’s count, Google came up with half a million hits when he entered “Einstein” and “biggest blunder.”
According to Livio’s version of the story, general relativity, published in 1916, predicts that the universe is unstable and should either be expanding or contracting. At the time, scientists thought the universe was static and stable, and so to account for this, Einstein added a fudge factor called the cosmological constant.
Then, in the 1920s, astronomers observed that the universe was expanding. The cosmological constant turned out to be unnecessary. But did Einstein really declare it his “biggest blunder”?
Livio picked through Einstein’s publications and correspondence and found that the great scientist was happy to abandon the cosmological constant because he considered his theory of general relativity to be more elegant without it. He didn’t express any regret at having proposed it in the first place.
Livio wrote that while some people assume Einstein lost his chance to predict an expanding cosmos, Einstein expressed no such regrets. The expanding universe isn’t something Einstein seems to have thought he could have foreseen.
Where did the “biggest blunder” story come from? Livio found it in the writings of fellow physicist George Gamow, who had a reputation as a jokester and a teller of tall tales – just the kind of person who would have been thrilled that people were repeating his meme in the 21st century.
Livio did find one place where Einstein allegedly referred to his “greatest mistake” but it had little to do with the cosmological constant. It was recorded in the diary of Linus Pauling, from a conversation that allegedly took place in 1954. According to Pauling, Einstein told him that his “greatest mistake” in life was “signing a letter to President Roosevelt recommending that atoms bombs be made.”
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